Portable fire-escape tower.



6 Smets-sheet l.

.l o 9 I.. 57 2 ..D. e F.. .d e t n e t a P E A D c A M P. 7. 8, 3 9 60. N

PORTABLE FIRE vES'CPE TGWER.

(No Model.)

.- witnesses TH Noam vereis on.: PHoToLrrH. wAsMlNG'roN, D. CA

un. 693,877'. a v- Patented Febi 25, |902,A

P.mcnAx-:. PORTABLE FIRE ESGAPETOWER.

, (Application med annals, 1901.) (No MudelJ' SShoets-Shaet 2.

No. 693,877. Patented Feb. 25, y|302.

P. M'AGVRAE. PORTABLE FIBE ESCAPE TOWER. (Ammann-mea mums, 1901.-) (NoModel.) 6 Sheete--Slieet 3.

A Patented F'eh-.\ 25,1902. P. MAcRAE.

PORTABLE FIRE ESCAPE TOWER.

(Application mea June 13,1901.)

(No Model.)

y @Morneys 'THE Nonms PETERS oq.. PHcTo-UTNOA. wAsHlNmoN. D. c.

No. 693,877. Patented Feb. 25,1902.

' P.MAcRAE.

PDRTABL'E FIRE ESCAPE lTLLWER.`

(Application tiled June 18, 1901.)

6 Sheets-Silent 5.

(No Model.)

Patented Feb. 25, |902.

- P. mums. PDRTABLE FIBETESGAPE TOWER.

' (Application tiled-June 13, 1901.)

6 Sheets-I-Sbeet 6.

(No Model.)

abb

feferzza Rd@ HVQNIOR UNITED gratins PATENT CFF-ICE.

PETER MACRAE, OFy ESCANABA, MICHIGAN.

`PORTABLE. FI RE1-ESCA'PE'TOWER.

SECEEICALIN fo'rril'ngl partuof Letters Patent No. 693,877, datedFebruary 25, 19.0.2.

` Y Application filed June 13,1901. Serial No. 64,404. (No model.)

` To all whom t 711/614./ concern:

Be it known that I, PETER MACRAE, a citizen of the United StatesofAmerica, residing at Escanaba, county of Delta, State of Michigan, haveinvented certain new and useful Imrovements in Portable Fire-Esca eTowers'- 9 and I do hereby declare that the following is a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use thesame.

My invent-ion relates to improvements in" portable fire-esca pe towersof that class which employ a lazy-tongs construction adapted to befolded compacily upon a wheeled truck.

One object of the invention is to provide a simple construction oflazy-tongs tower equipped with ladders which are foldablel and loweringof the tower being performed by or from a single prime shaft, which isdriven in one direction only during the period when it is in service.

A further object is tol provide means operable from the single primeshaft for giving a shiftable adjustment to the lazy-tongs towerindependent of the raising orlowering thereof, whereby the tower may bemoved in a transverse direction, so as to assumea leaning position, andhaving its upper endlie close to a building while the truck may bestationed in the middle of the street.

A further object of the invention is to provide means for swinging thetowerto different angular positions relative to the wheeled truck, suchswinging mechanism being driven from the single prime shaft, so as togive the desired adjustment to the tower or to return it to normalposition, and such mechanism being operable independently ofthe raisingand lowering mechanism and of the towershifting mechanism.

A further object of theinvention is to provide an improved escapemechanism by which women, children, and men may be safely and quicklylowered from an elevated story to the ground, the escape cage or basketVbeing raised for another load by motion derived through a train ofgearing from the single prime shaft.

Further objects and advantages ot'` the invention will appear in thecourse of the subjoined description, and the novelty in the combinationof mechanisms and in the construction and arrangement of parts `will bedefined by the claims.

In the drawings hereto annexed, forminga part ofA thisspecitication,Figure 1 is a side elevation of my improved fire-escapetower, the dotted line illustrating the towerv raised to a positionperpendicular to the base and the full lines representingtlle tower in aleaning position, the bed occupying a normal relation to the wheeledtruck. Fig. 2 is a side elevation of the tower in the position shown fby dotted lines in Fig. l, except that the bed is shifted to a positionat right angles to the wheeled truck. Fig. 3 is an enlarged plan `Viewof the apparatus with a portion of the' of the dotted line 6 6 on Fig.3' looking in the direction of the arrow. Fig. 7 is avertical transversesection through a part ofthe shiftable bed, taken in the plane of thedotted line 7 7 on Fig. 4, looking in the direction of the arrow. Fig..8is an enlargedk detail View, in

front elevation, of the drum associated with the cable for thefire-escape cage. Fig. 9 is a vertical* transverse section in the planeof the dotted line 9 9 on Fig. 4 looking in the direction of the arrow.Fig. 10 is a vertical crosssection in the plane of the dotted line l0 10on Fig. 8, also looking in the direction of the arrow. Fig. V11 is ladetail vertical section IOO . through the tubular shaft and theshit'table 'drawin designates the wheeled truck, having the axle 6,provided with the carrying-Wheels 7, whereby theapparatus is madeportable. This truck is provided with the cross-rails 8 8, (see Fig. 4,)and the latter-mentioned cross-rail has the step-bearing 9, which isadapted to accommodate the lower end of the vertical shaft 13; The frameof the truck and the cross-rail 8 thereof have alined shaftbearings inwhich is journaled the horizontal prime shaft lO, the same beingprovided at its front end with the driving-pulley 11, which may berotated 'by a belt from an engine or other source of power, although anysuitable means may be provided for the operation of the shaft 10. Theinner portion of this shaft is provided with a bevel-gear 12, which hasinterlneshing engagement with a similar bevel-gear 14, that is securednear the lower portion of said vertical shaft 13. (See Fig. at.)

15 designates the bed of the tower, thesame being provided with acentral bearingplate 16. The wheeled truck has an annular metallic rack17 secured to its upper side, and the central bearing-plate 16 of thebed 15 is arranged very close to the central portion of this annularrack, whereby the bearing-balls 21 may be interposed between the centralportion of the annular rack and the bearingplate 1G, so that the bed maybe turned upon the wheeled truck. The vertical shaft 13 passes looselythrough the central portion of the annular rack 17, the center of thebearing-plate 16, and the framework of the shiftable bed 15, the upperend of said vertical shaft being journaled in a suitable bearing-plate13, secured to the upper side of the bed, and this shaft 13 is adaptedto serve as the axis on which thebed 15 maybe turned in a horizontalplane, and said shaft also serves to transmit the motion of the primeshaft 10 to the horizontal counter-shaft 22. `The annular fixed rack 17is provided with the internal gear-teeth 18, and to said rack 17 isfastened the fixed gear 19, the lat- 1er having `the teeth 20 on itsexternal periphery. The gear-teeth of the annular rack 17 and of the xedgear l19 are practically in opposing relation, so that a gear 64 of anadjusting-shaft (53 may be made to mesh either with the rack 17 or withthe xed gear 19 for the purpose of changing the relation of the bed `tothe wheeled truck, all as will be hereinafter more fully described. Thecountershaft 22 is arranged in a horizontal position above the primeshaft 10, and it is mounted insuitable bearings 23, which are providedon the bed, whereby the `counter-shaft is mounted on' and is shiftablewith the bed. The rear portion of the counter-shaft is provided with abevel-gear 2l, which has intermeshing engagement with a similarbevelgear 14, secured to the upper portion of the vertical central shaft13, and the front portion of said counter-shaft 22 is provided withanotherbevel gear-wheel 2i. It will be noted that the shaft 13 transmitsthe motion of the prime shaft 10'to the counter-shaft 22 and that thegears 14: 24. of the shafts 13 22 remain in mesh with each other at allpoints in the adjustment of the bed 15 upon the wheeled base 5.

designates a horizontal transverse shaft which is arranged at the frontportion of the shiftable bed 15 and is journaled in suitable bearings26, said transverse shaft lying at right angles to the v counter-shaft22 and being shiftable with the bed 15, so as to always maintain itsoperative relation to said counter-shaft and to the worm-shafts, whichwill be presently described. Said transverse shaft 25 is provided with abevel-gear 27, that has intermeshing engagement with the bevelgear 24 onthe counter-shaft `22, and the transverse shaft 25 is furthermoreprovided with two sets of bevel-gears, one set of which is indicated at28 28L and the other set at 29 29% (See Fig. 3.) All thesegears are madefast with the shaft, so as to rotate therewith, and the gears of eachset are disposed in opposing relation, so that they will face eachother.

31 designate the worm-shafts, the same being arranged in horizontalpositions on opposite sides of the counter-shaft 22 and journaled inproper bearings on the bed 15, so as to occupya shiftable relation tothe sets of opposing gears on the transverse shaft 25, each wormshafthaving means associated therewith so as to change its relation to theset 0f bevel-gears independently of the other worm-shaft. The worm-shaft30 is provided at its front portion with a bevel-gear 30, which isadapted to be shifted into intermeshing engagement with either thebevel-gear 28 or 28, and in like manner the other worm-shaft is providedwith a bevel-gear 3l, which may be adjusted to mesh with either of thegears 29 or 29. The front portion of each worm-shaft being shiftablewith relation to one set of the bevelgears, I` have provided means forsupporting the rear portion of said shaft in a manner to permit of itsshiftable adjustment, and this is attained by the employment of arounded head 32, which is loosely Iitted in a socket or cavity 33, whichis provided on the bed 15. (See Fig. 6.) The front portion of each shaft30 and 31 is journaled in a shiftable bearing 34, which is constructedto engage with a guideway on the cross-bar 3(5,the latter being securedto the framework of thebed 15. (SeeFigs-6and7.)Theadjustmentofthisslidable bearing 34 and the front portion of eachworm-shaft is effected by a lever37, which is fulerurned at 38 on across-bar 39, provided on the framework of the bed, and the lowerportion of this adjusting-lever 37 is connected operatively with theslidable shaft-bear- IOO IIO

ing 34 by a link 40. The lever is held in its adj usted position by alatch 41, that is mounted on the lever and is arranged to engage with anotched segment 42, which is secured on the cross-bar 39 of the bed15.Each wormshaft is adapted to be shifted by its lever 37 to either ofthree positions-to wit., when the lever is thrown over to the right inFig. 7 the bearing 34 and the worm-shaft 30 are shifted to the left, sothat the bevel-gear on said worm-shaft will have intermeshing engagementwith one of the opposing bevelgears on the transverse shaft 25.Byreversing the position of the lever 37 or moving it to the left inFig. 7 the bearing 34 and the front portion ot' the worm-shaft areshifted to the right in order that the bevel-gear on said worm-shaft mayhave intermeshing engagement with the other bevel-gear of the set on thetransverse shaft 25; but when the lever 37 is adjusted to a verticalposition, as

shown by Fig. 7, the slidable'bearing and the front portion of theworm-shaft are positioned midway between the opposing bevelgears of theset, thus throwing the wormshaft bevelgear out of engagement with eitherof the opposing bevel-gears.

The worm-shafts 3031 are provided near their rear ends with the worms 4344, respec tively, and said worms are arranged to intermesh with theworm-gears 45 46, which are.

loosely mounted near the lopposite end portions of a pivotal shaft 47,the latter being mounted in suitable bearings 47 7, provided on theframework of the shiftable bed near the middle portion thereof. Each ofthe. shafts being shiftable independently of the other:

worm-shaft by proper adjustment of the lever 37 ,it is evident that thetwo worm-shafts may be driven simultaneously in the same direction inorder to turn the worm-gears 45 46 in the same direction; or oneworm-shaft may be thrown out of operation and the other worm- -shaft mayremain in service and in engagement with one of the set of bevelgears,soas to operate one of the worm-gears 45 46, for a purpose which willhereinafter be described. The pivotal shaft 47 serves to support theweight of the tower, which is of thelazy-tongs construction shown by thedrawings, and in view of this fact it is necessary to make said shaft 47quite substantial in construction.v

48 48L 48b designate one set of the tower members or links, which aremade fast one with the other and with the worm-gear 45, because themember 48 is secured rigidly to said worm-gear 45,and all of the membersor links 48 48a 48b are united solidly together by a cross-bar 48,all ofsaid members or links having their inner portions fitted loosely on thepivotal shaft47 The other set of links or tower l members 49, 49, and49b are made fast with the other worm-gear 46 and with each otherbecause the member 49 is secured firmly to the worm-gear 46,.and themembers 49"L 49b are joined rmly to each other and to the member 49 byanothercross-bar 49e, all of the construction is continuous throughoutthe height ofthe tower in order to make the latter extensible to thedesired height.

I prefer to equip thellazy-tongs towerwith a seriesof ladders,(indicated by the numerals 54 55,),as represented more clearly by Fig.2. Each ladderl 54 extends parallel with the links 48 50, while theother ladders areparallelt to the links or members 5l. Each ladder hasone end attached or connected in a suitable way toone of the cross-rods53,. while its other end rests upon the other cross-rod, and the laddersprovide means wherebya fireman may ascender descend the tower in azigzag path. The upper portion of the tower is equipped with anauxiliary lladder 56, which is pivotally connected at ,57 to thezuppermembers 51 Vof the tower, and 'this ladder is adapted to be adj ustedbeyond the toWer,- as representedV by Fig. 1, or it may be folded overupon` the tower, as shown by Fig. 4`

l will now proceedto describethe Ameans by which the shiftable bed 15may be adjusted across the wheeled truck or back to its normal position.Y

59 designatesa slidable carriage which is arranged in a horizontallposition between two of the rails of the bed-frame 15, and said carriageis provided inits sideedges with the grooves 60, the same adapted toreceive-the guide-ribs 6l, which are made fast with lthe -IOO frame-ofthe shiftable bed, as more clearly a vertical adjusting-shaft 63, thelowerv portion of which is provided with a spur-gear64,4 while the upperportion is equiped with a bevel-gear 65. (See Fig.'4.) l 64 of saidshaft is arranged between the internally-toothed rack 17 and the fixedvgear 19 and according to the position of the4 carriage 59, and this gear64 is adapted to mesh with the fixed gear 19 orwith the rack 17.

The spur-gear The adjusting-,shaft 63 is adapted to be driven I from thecounter-shaft 22, which, it will be recalled, is driven by the shaft 13from theprime shaft 10, 'and to accomplish this endl' provide theslidable carriage :59with an upstanding arm 66, which' is constructedwith a bearing 67, that is sleeved on the countershaft 22. Thecounter-shaft 22 is provided -contained parts may easily"y be effected.j usting-shaft 63.

cured to the bed-frame.

with a longitudinal key or feather 68, and in the bearing 67 is looselyfitted a tubular shaft 69a, the same having a groove which receives the`feather GS, and said tubular shaft is furthermore provided with abevel-gear 69, that is arranged to have intermeshing engagement with thebevel-gear 65 on the vertical ad- It will be observed that the shaft 63and its two gears are adjustable with the carriage and that the tubularshaft (39, with the gear 69, is also adjustable with the carriage;` butthe tubular shaft and its gear being splined to the counter-shaft themotion of the latter will be transmitted by the gears (i9 and 65 to theadjusting-shaft 63 at all points of its adjustment, whereby the gearingwill transmit the motion of the counter'- 4shaft 22 to the pinion 64when itis desired to shift the position of the bed.

The adjustment of the carriage 59 and its through the medium of a lever70, which is yfulcrumed at a point intermediate of its length on a studof aplate 71, that is fixed to a portion of the framework ofthe shift-.able bed. The lower portion of this lever is `connected by a link 72 tothe carriage, and `the upper portion of said lever is equipped lwith alatch 73, arranged to have engagement with a notched segment 74, whichis se- By moving thelever in one direction the carriage will be adjustedto make the gear 64 intermesh with the fixed gear 19, and tho motion ofthe shaft 22 will .cause the bed to swing or turn in one direc- `tionaround the axis aifordedby the vertical shaft 13, whereby the entire bed15 and the extensible tower may be adj usted to a position at rightangles to the length of the wheeled truck, as shown by Fig. 2. Areversal of the lever 70, however, will draw the `carriage in anopposite direction and `make `the gear 64 mesh with theinternally-toothed rack 17, and the described train of gearingtransmitsthe motion of the counter-shaft 22 to the pinion 64 for thepurpose of swinging the bed 15back to its normal alined relation to thetruck 5. Of course the carriage 59 may` be adjusted in a position whichplaces the pinion 64 free from engagement with the rack 17 and the gear19, thus allowing the bed 15 to remain at rest.

JIt. is` desired to provide means which will Alock the shiftable bedinits adjusted position, so as to maintain it steadily in place, and asone` means for accomplishing this end I have equipped` the bed 15 withthe locking-posts 75 .75, the same arranged at the rear corners ofvposts 75 75 firmly into engagement with the ground, whereby said postsserve to steady the bed in its adjusted positions.

With the apparatus I have associated iireescape devices adapted toquickly and safely transport a person from an upper story of a burningbuilding to the ground, and these devices are operable independently ofthe other services for which the apparatus is designed. I employ anescape-cable 82, which is guided by suitable sheaves 83 S4 at the frontand rear upper portions of the tower, one end of this cable beingconnected to a suitable basket or cage S5. The otherend of the cable iscoiled around a drum 8(5,that is loosely mounted on a shaft 87, so as tobe free to slide endwise thereon and to rotate on its axis. This shaftis journaled in suitable bearings S8, provided on the frame of theshiftable bed, as shown more clearly by Fig. S, and to the shaft issecured a gear-pinion 89, which has intermeshing engagement withaspur-gear 90, that is made fast with the transverse shaft 25, (seeFigs. 3 and 4,) whereby the drum-shaft may be driven by-motion derivedfrom said transverse shaft 25. This shaft 87 is also provided withafastclutch member 91, that is in opposing relation to a shiftable clutchmember 92, which is provided on the drum S6, and this drum is providedat its opposite end portion with a groove 93, that is arranged toreceive the pins 94a of a shipper-lever 94, the latter being fulcru medto the framework of the bed and having its handle end disposed inconvenient position, as shown more clearly by Fig. 3. The drum isfurthermore provided with a brake-surface 9G, which is partiallyenpermit the basket and its load to descend by gravity, and thereby drawon the cable 82, so as to uncoil said cable from the drum. After theload is discharged from the basket or cage the brake is released and thelever 94 is adjusted in a direction to move the drum 86 to a positionwherein the clutch member 92 will engage with the clutch member 91. The

drum is thus made fast with the shaft, and Vthe latter is rotatedthrough the gears S9 90, whereby the cable 82 may be coiled on the drum,so as to raise the cage or basket into position to receive another load.

The operation of the apparatus may bc sum- ICO IIO

mal-ized as follows: With the drum-shaft 10 constantly rotating in onedirection it is necessary to shift the levers 37 to the positionsindicated in Fig. 2 when it is desired to raise the tower to a verticalposition, which is indicated by dotted lines in Fig. l. The adjustmentof the levers 37 to the prescribed positions moves the shafts 30 3l, sothatl the gears 30a and .Sla will-have intermeshing engagement with thegears 28 and 29, whereby theA shafts 30 81 will both be brought intoservice for rotation in a common direction and adapted to drive the twoworm-gears 45 46 with equal angularvelocity. These wormgears will beturned in corresponding directions and impart motion to the lazy-tongstower, whereby the latter will be extended or unfolded in a planeperpendicular to the shiftable bed l5 and as represented by dotted linesin Figl; To lower the tower toits folded compact position upon thetruck, (shown by Fig. 4,) the levers 37 are adjusted in order to reversethe positionsof the shafts 30 3l and make the bevel-gears ()n 31W haveintermeshing engagement with the gears 28L 29iL on the transverse shaft,whereby the two worm-shafts will be simultaneously rotated in thereverse direction, so as to impart like motion, and with equal angularvelocity, to the worm-gears. One advantage'of the wormgear between theshafts 30 3l and the lower elements of the toweris that the parts of thetower will be locked in position, which is especially advantageouswhenthe tower is extended or adjusted for service, because theworm-gearing dispenses with separate locking mechanism. If the tower israised to its vertical position and it" is desired to'give a leaningappearance thereto in a direction to-` ward the rear part of theapparatus, as shown by full lines in Fig. l, theV worm-shaft 3l isadjusted for its bevel-gear l3la to lie between and out of mesh with theset of bevel-gears 29 29h-whereas the other worm-shaft 30 is adjusted soas to make its bevel-gear 30a engage with the bevel-gear 28. The motionof the transverse shaft 25 is thus transmitted, Ithrough the gears 2S30a, to the shaft 30, which turns one worm-gear 45 of the two worm-gears45 46 on the pivotal shaft, and thus the members 48 48 48h of the towerwill be raised and the other parts of the tower will be shifted, so astov make the structure assume the leaning position represented by Fig.l. To bring thetower back to its vertical position, it is necessary toreverse the worm-shaft 30 in a direction to bring its gear 30a into meshwith the other gear 28 of the set of opposing bevel-gears on thetransverse shaft, and thus the tower may be given the leaning adjustmentor brought back to nor'- mal position byv motion derived from the primeshaft. f

The position of the bed l5 on the truck may be changed either when thetower is in its unfolded position orin its extended position,

v is moved in an opposite direction and the 'gear 64 mesheswith the rack17.

The locking-posts '75a may be brought into service when the bed isshifted to its transverse position, and the escape-cage and its cablemay `also be employed at any period in the adjustment or service of thetower except when the latter is folded.

Changes within the scope of the appended i claims may be made inthe formand proportion of some of the parts while their essential features areretained and the spirit of the invention is embodied. Hence I do notdesire to be limited to the precise f orm of all the parts as shown,reserving the right tovary therefrom. n

Having thus described my invention,what I claim as new is l. In anapparatus of the class described, the combination with a lazy-tongstower,of a pivotal shaft on which the lower members of the tower aremounted, gear elements secured fast to dilferent sets of the towermembers vand adapted to independently or simultaneously actuate thesame, adjusting-shafts operatively connected with said gear elements, asingle transverse shaft disposed adjacent to said adjusting-shafts andprovided with sets of facing gears adapted to mesh separately with gearson the adjusting-shafts, means for rotating the transverse shaftin onedirection, and means for individually shifting the adjusting-shafts intomeshing relation to either of the sets ofr gears on the trans-l verseshaft, as and for the purposes described. j

2. In an apparatus of the class described, the combination of a wheeledtruck, a bed shiftably mounted thereon, a lazy-ton gs tower supported bythe bed, a prime shaft mounted on the truck, a transverse shaft'and acoun.-`

.ter-shaft mounted on the bed and driven'from the prime shaft, shiftabletoweradjusting.

shafts mounted on the bed and adapted to be driven individually orcollectively from the transverse shaft for raising, lowering orinclining the tower by motion derived from the prime shaft,andb'ed-adjusting devices having means geared tothe connter-shaftand tothe truck for swinging the bed audits contained tower on a verticalaxis, substantially as described. y

3. In an apparatus of the class described,

the combination of a pivotal shaft, the wormgears loosely mountedthereon, a lazy-tongsy tower having its lower members loosely mounted onthe pivotal shaft vand with the different sets of lower members madefast with the worm-gears individually, the worm.- shafts looselysupported at one end and'operatively connected with the worm-gears, atransverse shaft provided with different sets of facingbevel-gears, and'means forshiiftably IOC IIO

supporting the free ends of the worm-shafts with relation to said facingsets of bevelgears, substantially as described.

4. In an apparatus of the class described, the combination of a pivotalshaft, Wormgears individually mounted thereon, a tower having itslowermembers made fast with the worm-gears respectively, a transverseshaft provided with sets of facing gears, cross-bars adjacent to thetransverse shaft, shaft-bearings slidably mounted on the cross-bars andhaving suitable means for individuallj)T 0perating the same, worm-shaftsloosely supported at one end, journaled at their other ends in the shiftable shaft-bearings and having interln eshing engagement with thewormgears, and bevel-gearsv on the worm-shafts and arranged to beengaged with either bevelgears of the sets and to be free fromengagement therewith, substantially as described.

5. In an apparatus of the class described, the combination of a wheeledtruck, a shiftable bed thereon, a prime shaft carried by the truck, alazy-tongs tower mounted on the bed, the transverse shaft on the bed,the shiftable worm-shafts mounted on the bed and geared to worm-gears onthe tower-sections and adapted to be driven by the transverse shaft, acounter-shaft geared to the transverse shaft and to the prime shaft,opposing gears mounted on the truck and a shiftable carriage, and ashaft journaled in the carriage and driven from the counter-shaft andadapted to engage with either of said opposing gears, substantially asdescribed.

(i. In an apparatus of the class described, the combination of a wheeledtruck, a bed `shiftable thereon, a tower supported by the bed, a primeshaft, a vertical shaft geared to the prime shaft, a counter-shaftdriven from the vertical shaft, the fixed gear and the anuular racksupported by the wheeled truck, a

the` combination of a Wheeled truck, a shiftl able bed mounted thereonand carrying a tower, a fixed gear on the truck, an internally-toothedrack fixed to the truck, a slidable carriage on the bed, a shaft mountedin the carriage and having a gear arranged to mesh either with the fixedgear or with the annular rack, means for adjusting the'carriage, andmeans for rotating the shaft in thecarriage, substantially as described.

8. In an apparatus of the class described, the combination of a wheeledtruck, a shiftable bed thereon, a fixed gear on the truck, aninternally-toothedrack fixed to the truck, a counter-shaft mounted onthe bed and provided with a spline, a tubular shaft engaging with thecounter-shaft and its spline and having a bevel-gear, a carriageslidably fitted on the bed and provided with two bearings, one of whichsupports the tubular shaft, an adjusting-shaft mounted in the carriageand having a bevel-gear which intermeshes with the first-namedbevel-.gear and provided with a spur-gear arranged to engage either withthe rack or with the fixed gear, a lever connected with the carriage,and means for rotating the counter-shaft, substantially as described.

In witness whereof I have hereunto set my hand in the presence of twowitnesses.

PETER MACRAE.

